Genetics of glucocorticoids in asthma

GLCCI1 and STIP1 variants are associated with asthma susceptibility and inhaled corticosteroid response in a Tunisian population

Objective: Pharmacogenetic studies have recognized specific genes that highly correlate with response to inhaled corticosteroids (ICS) treatment in asthma patients. Among the genes identified, we selected glucocorticoid-induced transcript 1 (GLCCI1) and stress-induced phosphoprotein 1 (STIP1) to evaluate the impact of these gene polymorphisms on ICS treatment response in Tunisian asthmatics.Methods: We analyzed four single nucleotide polymorphisms (SNPs): two in GLCCI1 (rs37972 and rs37973), and two in STIP1 (rs2236647 and rs2236648), which are genes associated with susceptibility to asthma and response to ICS in a Tunisian cohort. The SNPs were genotyped using reverse transcriptase polymerase chain reaction (RT-PCR) techniques.Results: This case-control study consisted of 230 adult asthmatic patients and 236 healthy subjects. Seventy-five asthmatics were selected and followed through 12 weeks of routine treatment. The T allele rs2236648 in STIP1 was associated with allergic asthma (OR = 0.38, 95%CI = 0.20-0.69, p = 0.001). The rs37972 and rs37973 of GLCCI1 were associated with a higher risk of asthma (p < 0.001). The T allele rs37972 and G allele rs37973 were correlated with a strong risk for developing severe asthma (p < 0.001). Asthma patients carrying the rs37973 GG genotype had less improvement in the forced expiratory volume in one second (FEV1) than those with the AA or AG genotypes after 12 weeks of treatment (p < 0.001). Also, the G allele of rs37973 was associated with worse response to ICS after 12 weeks of treatment (p < 0.001).Conclusion: The rs37972 and rs37973 polymorphisms can serve as potential asthma risk biomarkers in a Tunisian population.

Pharmacological Management of Chronic Obstructive Lung Disease (COPD). Focus on Mutations - Part 1

BACKGROUND

We report a comprehensive overview of current Chronic Obstructive Lung Disease (COPD) therapies and discuss the development of possible new pharmacological approaches based on "new" knowledge. Specifically, sensitivity/resistance to corticosteroids is evaluated with a special focus on the role of gene mutations in drug response.

OBJECTIVE

Critically review the opportunities and the challenges occurring in the treatment of COPD.

CONCLUSION

Findings from "omics" trials should be used to learn more about biological targeted drugs, and to select more specific drugs matching patient's distinctive molecular profile. Specific markers of inflammation such as the percentage of eosinophils are important in determining sensitivity/resistance to corticosteroids. Specific gene variations (Single nucleotide polymorphisms: SNPs) may influence drug sensitivity or resistance. Clinicians working in a real-world need to have a suitable interpretation of molecular results together with a guideline for the treatment and recommendations. Far more translational research is required before new results from omics techniques can be applied in personalized medicine in realworld settings.

FKBP5 rs4713916: A Potential Genetic Predictor of Interindividual Different Response to Inhaled Corticosteroids in Patients with Chronic Obstructive Pulmonary Disease in a Real-Life Setting

Background: Chronic obstructive pulmonary disease (COPD) is a common, preventable, and manageable lung disease characterized by large heterogeneity in disease presentation and grades impairment. Inhaled corticosteroids (ICS) are commonly used to manage COPD/COPD-exacerbation. The patient's response is characterized by interindividual variability without disease progression/survival modification. Objectives: We hypothesize that a therapeutic intervention may be more effective if single nucleotide polymorphisms (SNPs) are investigated. Methods: In 71 COPD patients under pulmonary rehabilitation, a small number of powerful SNPs, selected according to current literature, were analyzed; namely the glucocorticoid receptor gene NR3C1 (rs6190/rs6189/rs41423247), the glucocorticoid-induced transcript 1 gene (GLCCI1 rs37972), and the related co-chaperone FKBP5 gene (rs4713916). MDR1 rs2032582 was also evaluated. Lung function outcomes were assessed. Results: A significant association with functional outcomes, namely FEV₁ (forced expiration volume/one second) and 6MWD (six-minutes walking distance), was found for rs4713916 and weakly for rs37972. The genotype rs4713916(GA) and, in a lesser extent, the genotype rs37972(TT), were more favorable than the wild-type. Conclusions: Our study supports a possible picture of pharmacogenomic control for COPD intervention. rs4713916 and, possibly, rs37972 may be useful predictors of clinical outcome. These results may help to tailor an optimal dose for individual COPD patients based on their genetic makeup.

Donor Genotype and Intragraft Expression of CYP3A5 Reflect the Response to Steroid Treatment During Acute Renal Allograft Rejection

BACKGROUND

Glucocorticoid (GC)-refractory acute rejection (AR) is a risk factor for inferior renal allograft outcome. We investigated genetic predisposition to the response to steroid treatment of acute allograft rejection.

METHODS

Single nucleotide polymorphisms of genes involved in GC signaling (GR, GLCCI1) and drug metabolism and transport (CYP3A5, ABCB1, and PXR) were analyzed in kidney transplant recipients (1995-2005, Leiden cohort, n = 153) treated with methylprednisolone. Significant associations were verified in a second cohort (Berlin cohort, n = 66).

RESULTS

Patients who received a CYP3A5*1 allele expressing allograft had a lower risk of resistance to methylprednisolone during AR (odds ratio, 0.29; 95% confidence interval, 0.11-0.79; P = 0.016 in combined cohorts analysis). No differences were observed for GC signaling or other drug metabolism/transport-related genes. Both before transplantation (n = 69) and at time of AR (n = 88), tissue CYP3A5 mRNA expression was significantly higher in CYP3A5*1 allele expressing donor kidneys than in CYP3A5*3/*3 allografts (P < 0.00001). Moreover, steroid-responsive patients (n = 64) expressed significantly higher intragraft CYP3A5 mRNA levels compared to steroid-refractory patients (n = 42) in AR (P = 0.006).

CONCLUSIONS

CYP3A5 protein expression was detected in tubular epithelial cells and inflammatory cells within the grafts. Our findings show that steroid resistance during AR is associated with donor genotype and intragraft expression levels of CYP3A5.

GLCCI1 rs37973: a potential genetic predictor of therapeutic response to inhaled corticosteroids in Chinese chronic obstructive pulmonary disease patients

Inhaled corticosteroids (ICSs) are widely prescribed in chronic obstructive pulmonary disease (COPD). However, little is known about predictors of ICSs therapeutic response. To investigate whether the variation in glucocorticoid-induced transcript 1 (GLCCI1) rs37973 is associated with ICS efficacy. A total of 204 clinically stable COPD patients were recruited and administered to inhaled fluticasone propionate/salmeterol combination (500/50 ug, twice daily) for 24 weeks. We genotyped the functional rs37973 and mainly assessed its effects on changes in lung function. In vitro, neutrophils isolated from parts of patients were incubated with various concentrations of dexamethasone (0, 10⁻⁶ M and 10⁻⁴ M) in the presence or absence of cigarette smoke extract, apoptosis was then assessed by flow cytometry. Patients with the homozygous GG genotype (increases of 15.3 ± 33.2 mL) had significantly poorer improvement in FEV₁ than those with the AA (92.7 ± 29.6 mL; p < 0.001) or AG (59.4 ± 26.9 mL; p < 0.001) genotypes after 24-week treatment. In vitro, dexamethasone had less inhibitory effect of neutrophil apoptosis on GG genotype, which further validated the presence of mutant allele ‘G’ might negatively affect glucocorticoid responsiveness irrespective of smoking status. The GG genotype of rs37973 may associated with decreased ICSs efficacy in Chinese COPD patients.

Haemophilus influenzae responds to glucocorticoids used in asthma therapy by modulation of biofilm formation and antibiotic resistance

Glucocorticosteroids are used as a main treatment to reduce airway inflammation in people with asthma who suffer from neutrophilic airway inflammation, a condition frequently associated with Haemophilus influenzae colonization. Here we show that glucocorticosteroids have a direct influence on the behavior of H. influenzae that may account for associated difficulties with therapy. Using a mouse model of infection, we show that corticosteroid treatment promotes H. influenzae persistence. Transcriptomic analysis of bacteria either isolated from infected mouse airway or grown in laboratory medium identified a number of genes encoding regulatory factors whose expression responded to the presence of glucocorticosteroids. Importantly, a number of these corticosteroid-responsive genes also showed elevated expression in H. influenzae within sputum from asthma patients undergoing steroid treatment. Addition of corticosteroid to H. influenzae led to alteration in biofilm formation and enhanced resistance to azithromycin, and promoted azithromycin resistance in an animal model of respiratory infection. Taken together, these data strongly suggest that H. influenzae can respond directly to corticosteroid treatment in the airway potentially influencing biofilm formation, persistence and the efficacy of antibiotic treatment.

Polymorphisms in the glucocorticoid receptor gene and in the glucocorticoid-induced transcript 1 gene are associated with disease activity and response to glucocorticoid bridging therapy in rheumatoid arthritis

Glucocorticoids (GC) are widely used in rheumatoid arthritis (RA). Ongoing active disease due to GC resistance may unfavorably influence long-term disease outcome in RA. We studied the association between the presence of glucocorticoid receptor (GR) and glucocorticoid-induced transcript 1 (GLCCI1) gene polymorphisms, which modulate GC sensitivity, and baseline disease activity score (DAS) and efficacy of GC bridging therapy in RA. We prospectively studied in vivo GC sensitivity in 138 patients with recent-onset or longstanding RA. In vivo GC sensitivity was expressed as the relative decrease in DAS following 2 weeks of standardized GC therapy. All patients were genotyped for the GR polymorphisms BclI (rs41423247), N363S (rs6195), 9β (rs6198), ER22/23EK (rs6189 + rs6190), and the GLCCI1 variant rs37972 and subsequently divided in groups carrying a polymorphism associated with increased GC sensitivity (BclI-G allele, N363S-G allele, GLCCI1-C allele) or decreased GC sensitivity (9β-G allele, ER22/23EK-A/A allele, GLCCI1-T allele). Differences in baseline DAS and relative decrease in DAS in the different genotype groups were analyzed using analysis of covariance and linear regression. Baseline DAS was higher in patients who carried polymorphisms of the GR and GLCCI1 genes associated with decreased GC sensitivity. GLCCI1 genotype, but not GR genotypes, was associated with improvement in DAS in male patients with RA. The GLCCI1 gene minor allele (rs37972) may be associated with less efficient GC bridging therapy in male RA patients. Carriers of the BclI-G, N363S-G, or GLCCI1-C alleles had lower levels of baseline disease activity, suggesting a role for the GLCCI1 and GR gene in regulation of GC sensitivity to endogenously produced cortisol.

Pharmacogenetics of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a complex genetic disease that develops as a result of the interaction of multiple susceptibility genes and environmental factors. Major therapeutic approaches include smoking cessation, treatment with bronchodilators and corticosteroid therapy. The goal of understanding the genetic defects in patients with COPD will be not only to redefine the disease phenotypes based on the genetic information, but also to alternatively approach patients based on the understanding of COPD pathogenesis, which will lead to improved clinical outcomes. Although there is no single ideal phenotype for COPD pharmacogenetic studies, thus far, most pharmacogenetics studies have focused on the role of variants in the β2-adrenergic receptor gene on bronchodilator response. The inconclusive results yielded by these studies highlight many of the difficulties researchers face in assessing the influence of genetic variants and in translating this to clinically relevant outcomes.

Glucocorticoid sensitivity in health and disease

Glucocorticoids regulate many physiological processes and have an essential role in the systemic response to stress. For example, gene transcription is modulated by the glucocorticoid-glucocorticoid receptor complex via several mechanisms. The ultimate biologic responses to glucocorticoids are determined by not only the concentration of glucocorticoids but also the differences between individuals in glucocorticoid sensitivity, which is influenced by multiple factors. Differences in sensitivity to glucocorticoids in healthy individuals are partly genetically determined by functional polymorphisms of the gene that encodes the glucocorticoid receptor. Hereditary syndromes have also been identified that are associated with increased and decreased sensitivity to glucocorticoids. As a result of their anti-inflammatory properties, glucocorticoids are widely used in the treatment of allergic, inflammatory and haematological disorders. The variety in clinical responses to treatment with glucocorticoids reflects the considerable variation in glucocorticoid sensitivity between individuals. In immune-mediated disorders, proinflammatory cytokines can induce localized resistance to glucocorticoids via several mechanisms. Individual differences in how tissues respond to glucocorticoids might also be involved in the predisposition for and pathogenesis of the metabolic syndrome and mood disorders. In this Review, we summarize the mechanisms that influence glucocorticoid sensitivity in health and disease and discuss possible strategies to modulate glucocorticoid responsiveness.